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Posted to users@tomcat.apache.org by Hartmut Honisch <ha...@gmail.com> on 2015/07/19 21:49:24 UTC
Parallel Deployment: Can I request a specific webapp version?
Hi everyone,
I'm using Tomcat's parallel deployment feature, and I wonder whether
there's a way to request a specific version of my webapp.
Let's say I have a WAR named myapp##001.war deployed on my server and just
deployed a new WAR myapp##002.war.
Requests to http:/myserver/myapp/.. are transparently mapped by Tomcat to
version 001 for existing sessions and to version 002 for new sessions.
Is there a way to explicitly request version 001, like
http://myserver/myapp##001/...? That specific syntax obviously doesn't
work, otherwise I wouldn't be asking :)
BTW: The reason I'm asking is because that transparent shift from one app
release to the next doesn't play along well with any caches (browser,
caching proxies, CDNs etc.):
When a shift to the next app release occurs, I generally need the client
browsers to fetch a fresh copy of all files belonging to that release. And
the only way to force them to do that is by having them use a different URL
than for the old app release files..
So my idea is to have the browser make an initial request to
http://myserver/myapp/redir.do, when launching the app, which
instantaneously redirects to the actual release-specifc URL
http://myserver/myapp##00x/... , thereby having the browser use
release-specific URLs for all application files.
Any help is appreciated.
Thanks
- Hartmut
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Konstantin Kolinko <kn...@gmail.com>.
2015-07-19 22:49 GMT+03:00 Hartmut Honisch <ha...@gmail.com>:
> Hi everyone,
>
> I'm using Tomcat's parallel deployment feature, and I wonder whether
> there's a way to request a specific version of my webapp.
>
> Let's say I have a WAR named myapp##001.war deployed on my server and just
> deployed a new WAR myapp##002.war.
> Requests to http:/myserver/myapp/.. are transparently mapped by Tomcat to
> version 001 for existing sessions and to version 002 for new sessions.
>
> Is there a way to explicitly request version 001, like
> http://myserver/myapp##001/...? That specific syntax obviously doesn't
> work, otherwise I wouldn't be asking :)
No.
Routing (mapping) is based on session identifier. If you can supply a
valid session identifier (cookie) for an older version of web
application, you will be routed to the old version. Otherwise, you get
the latest version of the web application.
> BTW: The reason I'm asking is because that transparent shift from one app
> release to the next doesn't play along well with any caches (browser,
> caching proxies, CDNs etc.):
> When a shift to the next app release occurs, I generally need the client
> browsers to fetch a fresh copy of all files belonging to that release. And
> the only way to force them to do that is by having them use a different URL
> than for the old app release files..
>
> So my idea is to have the browser make an initial request to
> http://myserver/myapp/redir.do, when launching the app, which
> instantaneously redirects to the actual release-specifc URL
> http://myserver/myapp##00x/... , thereby having the browser use
> release-specific URLs for all application files.
http://www.w3.org/Provider/Style/URI.html
Cool URIs don't change
If you need to force reload of a script of a css, a usual trick is to
append a query (with some app version token calculated at build time)
to the file path. I mean, the path to CSS / JS file in HTML text
produced by your web application.
There may be also some other schemes to embed version token in path to
those files and use RewriteValve or similar solution to strip away the
version token.
http://tomcat.apache.org/tomcat-8.0-doc/rewrite.html
Best regards,
Konstantin Kolinko
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Chris,
On 7/21/15 1:30 PM, chris derham wrote:
>>> BTW: The reason I'm asking is because that transparent shift
>>> from one app release to the next doesn't play along well with
>>> any caches (browser, caching proxies, CDNs etc.): When a shift
>>> to the next app release occurs, I generally need the client
>>> browsers to fetch a fresh copy of all files belonging to that
>>> release. And the only way to force them to do that is by having
>>> them use a different URL than for the old app release files..
>>
>> Or, you could use proper proxy-friendly cache-control response
>> headers for those resources. Why aren't you doing that?
>
> The OP's main thread here is asking about logical deployment.
> However as a sub-thread he is asking about caching. As Christopher
> replied in this thread, I will attempt to clarify what I think the
> OP is asking.
>
> If you have v1.0.0 of the app deployed, and it has sent cache for
> 1 day replies for javascript/image/css files, then this works
> fine. However as soon as you release the next version, the browsers
> won't send requests as they have a local cache. Christopher's reply
> was "use proper proxy-friendly cache-control response headers". IMO
> having the browser only query for such static resources as these
> daily is something that would be required to reduce calls. However
> this comes at the expense of causing this issue.
Of course.
> My first thought was to suggest that the OP somehow use ETag
> header combined with a version number. However if the browser is
> told to cache for 1 day, this won't work. Having said that, if your
> app did send an ETag which was a hash of the files contents, then
> it would auto download a new version if it had changed between
> v1.0.0 and v1.0.1.
The ETag won't help if the browser is convinced that the resource
should not go stale in the next e.g. 24 hours: the browser won't even
make a HEAD request for that resource, or a conditional-GET with an
If-Last-Modified header set. The user would have to do a full-refresh
(usually SHIFT-CTRL-R or equivalent) to re-check the ancillary files
e.g. .css, .js, etc.
> I think that this leaves 3 solutions
>
> 1) Gauge what your site can support in terms of many calls to
> static resources vs when a new version is rolled out. Perhaps a 5
> minute browser cache is ok. Or 60 mins. or 180 etc. It is a
> balancing act between reducing server calls for static content that
> hasn't changed and the time for an upgrade to appear in the
> browser
>
> 2) Adjust the source of the website such that each script/css/img
> tag contains a version number parameter. You could do this via
> pre-processing the source rather than manually. Then cache that
> for 365 days. If you release a new version, just update the
> number.
This is probably the best way to deal with files that have a true
"version" to them: once you sundown one version, you create a new URL
for the new version, etc. But for things like .css, I think it's
probably not necessary.
We have some GWT-based components where the version number of the .js
files is very important, and the browser can't just use the old
version of the script with new data and vice-versa. So we do version
those URLs, but it's not done at the context-path level.. it's done at
the resource level. So, something like this:
/context/path/to/js/my-awesome-tool.1.4.2.js
Then this doesn't even have anything to do with the current version(s)
available in parallel deployment. It also means that it will work if
you want to offload your static files to another server that knows
nothing about parallel deployment.
> 3) Set a cookie with the version number, and then redirect server
> side to different version specific urls.
Yuck.
> 2) seems to be the most robust to me. Christopher can you clarify
> what you meant?
I agree that #2 is probably best, but it depends on the circumstances.
- From what I've read here, I'd stick with #2.
- -chris
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by chris derham <ch...@derham.me.uk>.
>> BTW: The reason I'm asking is because that transparent shift from
>> one app release to the next doesn't play along well with any caches
>> (browser, caching proxies, CDNs etc.): When a shift to the next app
>> release occurs, I generally need the client browsers to fetch a
>> fresh copy of all files belonging to that release. And the only way
>> to force them to do that is by having them use a different URL than
>> for the old app release files..
>
> Or, you could use proper proxy-friendly cache-control response headers
> for those resources. Why aren't you doing that?
The OP's main thread here is asking about logical deployment. However
as a sub-thread he is asking about caching. As Christopher replied in
this thread, I will attempt to clarify what I think the OP is asking.
If you have v1.0.0 of the app deployed, and it has sent cache for 1
day replies for javascript/image/css files, then this works fine.
However as soon as you release the next version, the browsers won't
send requests as they have a local cache. Christopher's reply was "use
proper proxy-friendly cache-control response headers". IMO having the
browser only query for such static resources as these daily is
something that would be required to reduce calls. However this comes
at the expense of causing this issue.
My first thought was to suggest that the OP somehow use ETag header
combined with a version number. However if the browser is told to
cache for 1 day, this won't work. Having said that, if your app did
send an ETag which was a hash of the files contents, then it would
auto download a new version if it had changed between v1.0.0 and
v1.0.1.
I think that this leaves 3 solutions
1) Gauge what your site can support in terms of many calls to static
resources vs when a new version is rolled out. Perhaps a 5 minute
browser cache is ok. Or 60 mins. or 180 etc. It is a balancing act
between reducing server calls for static content that hasn't changed
and the time for an upgrade to appear in the browser
2) Adjust the source of the website such that each script/css/img tag
contains a version number parameter. You could do this via
pre-processing the source rather than manually. Then cache that for
365 days. If you release a new version, just update the number.
3) Set a cookie with the version number, and then redirect server side
to different version specific urls.
2) seems to be the most robust to me. Christopher can you clarify what
you meant?
HTH
Chris
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Hash: SHA256
Hartmut,
On 7/19/15 2:49 PM, Hartmut Honisch wrote:
> Hi everyone,
>
> I'm using Tomcat's parallel deployment feature, and I wonder
> whether there's a way to request a specific version of my webapp.
>
> Let's say I have a WAR named myapp##001.war deployed on my server
> and just deployed a new WAR myapp##002.war. Requests to
> http:/myserver/myapp/.. are transparently mapped by Tomcat to
> version 001 for existing sessions and to version 002 for new
> sessions.
>
> Is there a way to explicitly request version 001, like
> http://myserver/myapp##001/...? That specific syntax obviously
> doesn't work, otherwise I wouldn't be asking :)
>
> BTW: The reason I'm asking is because that transparent shift from
> one app release to the next doesn't play along well with any caches
> (browser, caching proxies, CDNs etc.): When a shift to the next app
> release occurs, I generally need the client browsers to fetch a
> fresh copy of all files belonging to that release. And the only way
> to force them to do that is by having them use a different URL than
> for the old app release files..
Or, you could use proper proxy-friendly cache-control response headers
for those resources. Why aren't you doing that?
- -chris
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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George,
On 9/24/15 5:59 PM, George Sexton wrote:
> On 9/24/2015 4:35 AM, Linus Brimstedt wrote:
>> Hello,
>>
>> Opening an old thread here regarding controlling which version of
>> a web app a request ends up at in a parallell deployment
>> scenario.
>>
>> My use case: I would like to use parallel deployments for A/B
>> testing.
>>
>> I.e, deploy new version. Send x% of visitors to the new version,
>> the rest to the old one.
>>
>> Once conviced the new version is better, have traffic go
>> primarily to the new version and let the old one die.
>>
>> Next deploy, samt all over again.
>>
>> Someone mentioned controlling this through a cookie, however,
>> when I was checking my browsers requests I could find no signs of
>> a cookie controlling this (other than the normal session cookie,
>> but in this case i suppose this is meta data baked into the
>> session ? Could find my way around the code to verify this)
>>
>> Im not opposed to do some development here if there is not
>> support already and it would be approved. I would then prefer to
>> control the behaviour through a header which I can impose in a
>> load balancer or proxy fronting Tomcat. Other suggestions are
>> welcome.
>
> Couldn't you have your load balancer send x% to one instance, and
> 1-x% to the other instance? Why would Tomcat even have to be aware
> of this?
This is precisely what I was going to suggest: no hacks required. Just
upgrade one server and don't upgrade the rest. If there's a problem,
just roll-back that server or throw it out of the load-balancer.
- -chris
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Re: [OT] Re: Parallel Deployment: Can I request a specific webapp
version?
Posted by George Sexton <ge...@mhsoftware.com>.
On 9/24/2015 4:27 PM, André Warnier (tomcat) wrote:
> On 24.09.2015 23:59, George Sexton wrote:
> ...
>
>>
>> Couldn't you have your load balancer send x% to one instance, and
>> 1-x% to the other
>> instance?
>
> Wait, I didn't get this.
> Say that x = 20.
> So we send 20% to instance A.
> Then we send (1 - 20)% = -19%, to instance B.
My mistake. I thought most people would interpret my statement as
1.0 - 0.x
Since that isn't the case. I'll be explicit.
Could you have your load balancer send x% to one instance and 100%-x% to
the other instance.
> So together, instance A and instance B handle (20 + -19)% = 1% of the
> clients.
> What happens to the other 99% ?
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
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>
--
George Sexton
*MH Software, Inc.*
Voice: 303 438 9585
http://www.mhsoftware.com
[OT] Re: Parallel Deployment: Can I request a specific webapp
version?
Posted by "André Warnier (tomcat)" <aw...@ice-sa.com>.
On 24.09.2015 23:59, George Sexton wrote:
...
>
> Couldn't you have your load balancer send x% to one instance, and 1-x% to the other
> instance?
Wait, I didn't get this.
Say that x = 20.
So we send 20% to instance A.
Then we send (1 - 20)% = -19%, to instance B.
So together, instance A and instance B handle (20 + -19)% = 1% of the clients.
What happens to the other 99% ?
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Ludovic Pénet <l....@senat.fr>.
>> You have competing requirements:
>>
>> 1. All servers are the same
>>
>2. Some subset users get a different version of the application
>>
>
>All servers would have all versions of the app, thats the whole point
>:)
>I.e.
>Instead of
>Server 1 - 3: App Version 001
>Server 4 - 6: App Version 002
>
>I would have
>Server 1-6: App Version 001 + 002
>
>Parallel deployment makes this possible and simple to use.
As far as I understand (and use it on a daily basis), parallel deployment allows to upgrade a webapp to a new version with no downtime, new sessions being handled by the newest version and existing ones beinig handled by the version already handling them.
That the only case where I see parallel deployment using multiple versions. And so I see no case where new sessions arr handled by two different versions.
So, it seems to me that // deployment is not a fit for your requirements.
I find them interesting anyway, as I would really like to be able to have a finer control on the selection of the "current" version.
This would allow transparent downgrades, without removing or stopping a version and help solve a stupid problem I had several times : // deployment sort versions alphabetically. So, version 1.1.9 is prefered to 1.1.10, for instance...
Ludovic
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Linus Brimstedt <li...@viskan.se>.
Hi,
Ok, so to conclude this is not possible at the moment.
Thanks for the input and clarifications as well as the suggested ways to
work :)
br
/Linus
On 29 September 2015 at 00:16, Christopher Schultz <
chris@christopherschultz.net> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> Linus,
>
> On 9/28/15 2:37 AM, Linus Brimstedt wrote:
> > On 27 September 2015 at 23:55, Christopher Schultz <
> > chris@christopherschultz.net> wrote:
> >
> >>
> >> You have competing requirements:
> >>
> >> 1. All servers are the same
> >>
> > 2. Some subset users get a different version of the application
> >>
> >
> > All servers would have all versions of the app, thats the whole
> > point :) I.e. Instead of Server 1 - 3: App Version 001 Server 4 -
> > 6: App Version 002
> >
> > I would have Server 1-6: App Version 001 + 002
> >
> > Parallel deployment makes this possible and simple to use.
>
> Sure, you can push multiple versions of your application to all your
> servers, but the caveat is that all new users will be using the new
> application: you can't upgrade selected users (like your own QA
> testers, for instance). So this isn't an ideal solution, regardless of
> how simple it is.
>
> >> Sounds like they can't co-exist without some kind of compromise.
> >> We are offering one that works with currently-available
> >> software.
> >>
> >
> > Please elaborate
>
> We've already explained:
>
> 1. Upgrade some load-balanced nodes
> 2. wait (???)
> 3. Profit
>
> If you want your QA team to be able to use the new version of the
> application but none of your "real" users, then try something like this:
>
> 1. Remove N/f from your load-balancer and upgrade using parallel
> deplyment
> (N = # of nodes and f=some factor of nodes you want to use for
> testing)
> (Existing users will still see version V-1 while new users will
> see version V. The lb will not send new users to these servers,
> so nobody will see version V at all.)
> 2. Configure your QA team's browsers so that the lb allows them to
> go to the servers you have upgraded, and get version V
> 3. Proceed with testing
> 4. When you are satisfied, put the nodes from step #1 back into the lb
> normal rotation
> 5. Upgrade the remaining nodes whenever you feel comfortable
>
> This means that, for a time, not all servers are identical. But you do
> achieve your primary objective: blue/green production deployment with
> a private interstitial testing phase.
>
> Your prior use of parallel deployment did not meet your primary
> criterion: namely that it upgrades too many people at once.
>
> I think you have to decide which requirement is more important: the
> private testing phase (which my proposal achieves) or the consistent
> configuration of all servers (which your proposal achieves).
>
> I still believe your requirements are at odds with each other.
>
> - -chris
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>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
--
*Linus Brimstedt *
CTO
+46 70 - 683 98 54
linus.brimstedt@viskan.se
*Viskan Distanshandel System AB*
Druveforsvägen 8
504 33 Borås, Sweden
+46 33 - 20 60 20
www.viskan.se
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Linus,
On 9/28/15 2:37 AM, Linus Brimstedt wrote:
> On 27 September 2015 at 23:55, Christopher Schultz <
> chris@christopherschultz.net> wrote:
>
>>
>> You have competing requirements:
>>
>> 1. All servers are the same
>>
> 2. Some subset users get a different version of the application
>>
>
> All servers would have all versions of the app, thats the whole
> point :) I.e. Instead of Server 1 - 3: App Version 001 Server 4 -
> 6: App Version 002
>
> I would have Server 1-6: App Version 001 + 002
>
> Parallel deployment makes this possible and simple to use.
Sure, you can push multiple versions of your application to all your
servers, but the caveat is that all new users will be using the new
application: you can't upgrade selected users (like your own QA
testers, for instance). So this isn't an ideal solution, regardless of
how simple it is.
>> Sounds like they can't co-exist without some kind of compromise.
>> We are offering one that works with currently-available
>> software.
>>
>
> Please elaborate
We've already explained:
1. Upgrade some load-balanced nodes
2. wait (???)
3. Profit
If you want your QA team to be able to use the new version of the
application but none of your "real" users, then try something like this:
1. Remove N/f from your load-balancer and upgrade using parallel
deplyment
(N = # of nodes and f=some factor of nodes you want to use for
testing)
(Existing users will still see version V-1 while new users will
see version V. The lb will not send new users to these servers,
so nobody will see version V at all.)
2. Configure your QA team's browsers so that the lb allows them to
go to the servers you have upgraded, and get version V
3. Proceed with testing
4. When you are satisfied, put the nodes from step #1 back into the lb
normal rotation
5. Upgrade the remaining nodes whenever you feel comfortable
This means that, for a time, not all servers are identical. But you do
achieve your primary objective: blue/green production deployment with
a private interstitial testing phase.
Your prior use of parallel deployment did not meet your primary
criterion: namely that it upgrades too many people at once.
I think you have to decide which requirement is more important: the
private testing phase (which my proposal achieves) or the consistent
configuration of all servers (which your proposal achieves).
I still believe your requirements are at odds with each other.
- -chris
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For additional commands, e-mail: users-help@tomcat.apache.org
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Linus Brimstedt <li...@viskan.se>.
Hello,
On 27 September 2015 at 23:55, Christopher Schultz <
chris@christopherschultz.net> wrote:
>
> You have competing requirements:
>
> 1. All servers are the same
>
2. Some subset users get a different version of the application
>
All servers would have all versions of the app, thats the whole point :)
I.e.
Instead of
Server 1 - 3: App Version 001
Server 4 - 6: App Version 002
I would have
Server 1-6: App Version 001 + 002
Parallel deployment makes this possible and simple to use.
> Sounds like they can't co-exist without some kind of compromise. We
> are offering one that works with currently-available software.
>
Please elaborate
/Linus
>
> - -chris
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> -----END PGP SIGNATURE-----
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
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>
>
--
*Linus Brimstedt *
CTO
+46 70 - 683 98 54
linus.brimstedt@viskan.se
*Viskan Distanshandel System AB*
Druveforsvägen 8
504 33 Borås, Sweden
+46 33 - 20 60 20
www.viskan.se
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Linus,
On 9/27/15 2:41 PM, Linus Brimstedt wrote:
> On 24 September 2015 at 23:59, George Sexton
> <ge...@mhsoftware.com> wrote:
>
> Tomcat. Other suggestions are welcome.
>>
>> Couldn't you have your load balancer send x% to one instance, and
>> 1-x% to the other instance? Why would Tomcat even have to be
>> aware of this?
>>
>>
> Hi
>
> Sure I could. But I like all my servers to be identical. If one
> fails, or is taken out of load balancer due to maintenance, I want
> everything to proceed as if nothing.
>
> I could deploy two different context for this, or use two different
> Tomcats on the same machine, it's just that parallel deployment
> seems like a perfect fit.. except I cannot control the traffic ;)
You have competing requirements:
1. All servers are the same
2. Some subset users get a different version of the application
Sounds like they can't co-exist without some kind of compromise. We
are offering one that works with currently-available software.
- -chris
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To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Linus Brimstedt <li...@viskan.se>.
On 24 September 2015 at 23:59, George Sexton <ge...@mhsoftware.com> wrote:
Tomcat. Other suggestions are welcome.
>
> Couldn't you have your load balancer send x% to one instance, and 1-x% to
> the other instance? Why would Tomcat even have to be aware of this?
>
>
Hi
Sure I could. But I like all my servers to be identical.
If one fails, or is taken out of load balancer due to maintenance, I want
everything to proceed as if nothing.
I could deploy two different context for this, or use two different Tomcats
on the same machine, it's just that parallel deployment seems like a
perfect fit.. except I cannot control the traffic ;)
br
/Linus
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by George Sexton <ge...@mhsoftware.com>.
On 9/24/2015 4:35 AM, Linus Brimstedt wrote:
> Hello,
>
> Opening an old thread here regarding controlling which version of a web app
> a request ends up at in a parallell deployment scenario.
>
> My use case:
> I would like to use parallel deployments for A/B testing.
>
> I.e, deploy new version.
> Send x% of visitors to the new version, the rest to the old one.
>
> Once conviced the new version is better, have traffic go primarily to the
> new version and let the old one die.
>
> Next deploy, samt all over again.
>
> Someone mentioned controlling this through a cookie, however, when I was
> checking my browsers requests I could find no signs of a cookie controlling
> this (other than the normal session cookie, but in this case i suppose this
> is meta data baked into the session ? Could find my way around the code to
> verify this)
>
> Im not opposed to do some development here if there is not support already
> and it would be approved. I would then prefer to control the behaviour
> through a header which I can impose in a load balancer or proxy fronting
> Tomcat. Other suggestions are welcome.
Couldn't you have your load balancer send x% to one instance, and 1-x%
to the other instance? Why would Tomcat even have to be aware of this?
>
> (related question on serverfault:
> http://serverfault.com/questions/723944/can-you-redirect-a-user-to-a-specific-version-in-tomcats-parallel-deployment
> )
>
> br
> /Linus
>
> On 21 July 2015 at 19:21, Christopher Schultz <ch...@christopherschultz.net>
> wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA256
>>
>> Chris,
>>
>> On 7/21/15 11:07 AM, Chris Gamache wrote:
>>> +1 here. This would be nice to have a standard way to manage
>>> different logical versions of the same webapp to handle
>>> split-braining client and server code. That's my million dollar
>>> problem.
>>>
>>> So, the idea floated by this fine group of list participants was
>>> to deploy and use cookies that a reverse proxy would decode to send
>>> your users to different back ends. That only gets you halfway to
>>> where you're going. Say you have version 1.0 and 1.1. Any patches
>>> not requiring reload could be deployed with #001,#002, but you
>>> would need to deploy two or more of the same webapp to get
>>> different urls: /webapp-1.0 and /webapp-1.1. The whole idea of the
>>> parallel deployment is to get the old version of the webapp
>>> undeployed asap. If you have different logical versions that need
>>> to remain... Well, using the management servlet you can
>>> programmatically undeploy your obsolete webapps at your leisure.
>>>
>>> I'm sure there's always a better idea lurking around out there
>>> though.
>> I'm still not understanding the use case, here.
>>
>> In what scenario would you want to knowingly access an "older" version
>> of the web application than the latest, and at the same time *not* have
>> a session key that is valid in one of those older versions?
>>
>> - -chris
>> -----BEGIN PGP SIGNATURE-----
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>> -----END PGP SIGNATURE-----
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>>
>
--
George Sexton
*MH Software, Inc.*
Voice: 303 438 9585
http://www.mhsoftware.com
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Linus Brimstedt <li...@viskan.se>.
Hello,
Opening an old thread here regarding controlling which version of a web app
a request ends up at in a parallell deployment scenario.
My use case:
I would like to use parallel deployments for A/B testing.
I.e, deploy new version.
Send x% of visitors to the new version, the rest to the old one.
Once conviced the new version is better, have traffic go primarily to the
new version and let the old one die.
Next deploy, samt all over again.
Someone mentioned controlling this through a cookie, however, when I was
checking my browsers requests I could find no signs of a cookie controlling
this (other than the normal session cookie, but in this case i suppose this
is meta data baked into the session ? Could find my way around the code to
verify this)
Im not opposed to do some development here if there is not support already
and it would be approved. I would then prefer to control the behaviour
through a header which I can impose in a load balancer or proxy fronting
Tomcat. Other suggestions are welcome.
(related question on serverfault:
http://serverfault.com/questions/723944/can-you-redirect-a-user-to-a-specific-version-in-tomcats-parallel-deployment
)
br
/Linus
On 21 July 2015 at 19:21, Christopher Schultz <ch...@christopherschultz.net>
wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> Chris,
>
> On 7/21/15 11:07 AM, Chris Gamache wrote:
> > +1 here. This would be nice to have a standard way to manage
> > different logical versions of the same webapp to handle
> > split-braining client and server code. That's my million dollar
> > problem.
> >
> > So, the idea floated by this fine group of list participants was
> > to deploy and use cookies that a reverse proxy would decode to send
> > your users to different back ends. That only gets you halfway to
> > where you're going. Say you have version 1.0 and 1.1. Any patches
> > not requiring reload could be deployed with #001,#002, but you
> > would need to deploy two or more of the same webapp to get
> > different urls: /webapp-1.0 and /webapp-1.1. The whole idea of the
> > parallel deployment is to get the old version of the webapp
> > undeployed asap. If you have different logical versions that need
> > to remain... Well, using the management servlet you can
> > programmatically undeploy your obsolete webapps at your leisure.
> >
> > I'm sure there's always a better idea lurking around out there
> > though.
>
> I'm still not understanding the use case, here.
>
> In what scenario would you want to knowingly access an "older" version
> of the web application than the latest, and at the same time *not* have
> a session key that is valid in one of those older versions?
>
> - -chris
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> -----END PGP SIGNATURE-----
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
--
*Linus Brimstedt *
CTO
+46 70 - 683 98 54
linus.brimstedt@viskan.se
*Viskan Distanshandel System AB*
Druveforsvägen 8
504 33 Borås, Sweden
+46 33 - 20 60 20
www.viskan.se
Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
Chris,
On 7/21/15 11:07 AM, Chris Gamache wrote:
> +1 here. This would be nice to have a standard way to manage
> different logical versions of the same webapp to handle
> split-braining client and server code. That's my million dollar
> problem.
>
> So, the idea floated by this fine group of list participants was
> to deploy and use cookies that a reverse proxy would decode to send
> your users to different back ends. That only gets you halfway to
> where you're going. Say you have version 1.0 and 1.1. Any patches
> not requiring reload could be deployed with #001,#002, but you
> would need to deploy two or more of the same webapp to get
> different urls: /webapp-1.0 and /webapp-1.1. The whole idea of the
> parallel deployment is to get the old version of the webapp
> undeployed asap. If you have different logical versions that need
> to remain... Well, using the management servlet you can
> programmatically undeploy your obsolete webapps at your leisure.
>
> I'm sure there's always a better idea lurking around out there
> though.
I'm still not understanding the use case, here.
In what scenario would you want to knowingly access an "older" version
of the web application than the latest, and at the same time *not* have
a session key that is valid in one of those older versions?
- -chris
-----BEGIN PGP SIGNATURE-----
Comment: GPGTools - http://gpgtools.org
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Re: Parallel Deployment: Can I request a specific webapp version?
Posted by Chris Gamache <cg...@gmail.com>.
+1 here. This would be nice to have a standard way to manage different logical versions of the same webapp to handle split-braining client and server code. That's my million dollar problem.
So, the idea floated by this fine group of list participants was to deploy and use cookies that a reverse proxy would decode to send your users to different back ends. That only gets you halfway to where you're going. Say you have version 1.0 and 1.1. Any patches not requiring reload could be deployed with #001,#002, but you would need to deploy two or more of the same webapp to get different urls: /webapp-1.0 and /webapp-1.1. The whole idea of the parallel deployment is to get the old version of the webapp undeployed asap. If you have different logical versions that need to remain... Well, using the management servlet you can programmatically undeploy your obsolete webapps at your leisure.
I'm sure there's always a better idea lurking around out there though.
CG
> On Jul 19, 2015, at 3:49 PM, Hartmut Honisch <ha...@gmail.com> wrote:
>
> Hi everyone,
>
> I'm using Tomcat's parallel deployment feature, and I wonder whether
> there's a way to request a specific version of my webapp.
>
> Let's say I have a WAR named myapp##001.war deployed on my server and just
> deployed a new WAR myapp##002.war.
> Requests to http:/myserver/myapp/.. are transparently mapped by Tomcat to
> version 001 for existing sessions and to version 002 for new sessions.
>
> Is there a way to explicitly request version 001, like
> http://myserver/myapp##001/...? That specific syntax obviously doesn't
> work, otherwise I wouldn't be asking :)
>
> BTW: The reason I'm asking is because that transparent shift from one app
> release to the next doesn't play along well with any caches (browser,
> caching proxies, CDNs etc.):
> When a shift to the next app release occurs, I generally need the client
> browsers to fetch a fresh copy of all files belonging to that release. And
> the only way to force them to do that is by having them use a different URL
> than for the old app release files..
>
> So my idea is to have the browser make an initial request to
> http://myserver/myapp/redir.do, when launching the app, which
> instantaneously redirects to the actual release-specifc URL
> http://myserver/myapp##00x/... , thereby having the browser use
> release-specific URLs for all application files.
>
> Any help is appreciated.
> Thanks
> - Hartmut
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